It is very unlikely that your marriage would have been annulled by the Church without your knowledge. As a general rule, both spouses must be informed of the annulment proceedings undertaken by a marriage tribunal so that they may have the opportunity to defend their marriage bond. Only in very exceptional cases, such as when one spouse is considered a danger to the other spouse's life, can an annulment proceed without duly notifying both spouses.
That said, if an annulment was granted to your husband by the Church, it likely would have been granted in the diocese in which your husband was residing at the time he petitioned for the annulment. If you know which diocese that might be, you can contact that diocese and request assistance in finding out if an annulment was granted by the local diocesan marriage tribunal.
Annulments: What You Need to Know
by Jimmy Akin
Annulments and the Catholic Church
by Edward Peters